Synthetic heat-conducting oil and application thereof

Abstract

The invention provides synthetic high-temperature heat-conducting oil which comprises the following components in percentage by total weight: 50-88% of dicyclohexylbenzene; 5 to 40 percent of cyclohexyl biphenyl; 5 to 25 percent of hydrogenated tetraphenyl; 0 to 15% of methyl cyclopentyl cyclohexylbenzene; and 0-10% of methyl cyclopentyl biphenyl. The synthetic high-temperature heat-conducting oil disclosed by the invention is suitable for an LQD-340 organic heat carrier. The heat-conducting oil provided by the invention is applied to industries such as petrochemical engineering, synthetic fibers, synthetic resins, wood processing, nuclear fuel treatment, medicines, printing and dyeing and the like. The conduction oil adopting dicyclohexylbenzene, cyclohexylbiphenyl and hydrogenated quaterphenyl has better fluidity and lower kinematic viscosity, and is suitable for more application scenes, such as cold regions in winter. The material has better thermal stability and is suitable for long-term high-temperature use.

Description

Technical Field

[0001] The invention relates to a synthetic heat-conducting oil (particularly suitable for LQD-340 organic heat carrier) and its application. Background Art

[0002] As an efficient heat transfer medium, high-temperature heat carrier (heat transfer oil) is used to support industrial organic heat carrier boiler systems. It mainly implements the requirements of GB 23971-2009. Its key performance is thermal stability (i.e. the ability to resist thermal decomposition). When used, it also needs to have a low pour point and low kinematic viscosity to be suitable for a wider range of application scenarios. In 1929, Dow Chemical in the United States took the lead in developing a biphenyl-biphenyl ether mixture, named Dowtherm A, which was patented and applied to heating systems, thus creating a precedent for the production of heat transfer oil and opening up a new path for the industrial development of heat transfer oil. The melting point of biphenyl-biphenyl ether is 12°C. It is solid under low temperature conditions. It needs to be heated to liquid for filling, which brings inconvenience to use. Since the 1980s, with the rapid development of my country's polyester industry, hydrogenated terphenyl has been promoted and applied in my country, and has been extended to chemical fiber and other related petrochemical industries. At present, it is used in high-temperature synthetic heat transfer oils.

[0003] The basic raw material for the traditional preparation of hydrogenated terphenyl is pure benzene, which is made from the residue in the production process of refined biphenyl. At present, the "tubular method" is mostly used abroad, where benzene is passed through a red-hot pipe, and two benzene molecules lose one hydrogen atom each and combine with each other to produce biphenyl. This method of producing biphenyl by high-temperature cracking has an ideal conversion rate of only about 8-12%. When producing biphenyl, terphenyl is produced as a byproduct. Triphenyl is hydrogenated to produce hydrogenated terphenyl. The yield of terphenyl in this route is low, which seriously affects the supply of terphenyl, the raw material of hydrogenated terphenyl. Biphenyl production enterprises in my country all use benzene steam to pass through red-hot furnace tubes for condensation and dehydrogenation to produce biphenyl. The production methods of different manufacturers are basically the same, but the heating methods are different, so their energy consumption and material consumption vary greatly. The conversion rate of these traditional production processes is generally around 8-12%, and the output of terphenyl is about 10% of the output of biphenyl. Due to the extremely low yield of terphenyl, the energy consumption and cost of hydrogenated terphenyl are high, and the production capacity is severely limited by terphenyl. And the product has a higher kinematic viscosity under low temperature conditions (0 degree kinematic viscosity: ~1500mm 2 / s), and it is difficult to add at low temperatures. The thermal stability of traditional preparation methods cannot be adjusted, and it is often necessary to add additives to improve thermal stability and reduce the deterioration rate. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of poor low-temperature fluidity and poor thermal stability in the prior art and to provide a hydrogenated terphenyl type heat transfer oil having the characteristics of low pour point, good thermal stability and good low-temperature fluidity.

[0005] In the first aspect of the present invention, there is provided a synthetic high-temperature heat transfer oil which, based on the total weight of the heat transfer oil, contains:

[0006] 50-88% of dicyclohexylbenzene;

[0007] 5-40% of cyclohexylbiphenyl;

[0008] 5-25% of hydrogenated terphenyl;

[0009] 0-15% of methylcyclopentylcyclohexylbenzene;

[0010] 0-10% of methylcyclopentylbiphenyl.

[0011] The synthetic high-temperature heat transfer oil of the present invention is particularly suitable for LQD-340 organic heat carriers.

[0012] In the second aspect of the present invention, there is provided the application of the above-mentioned heat transfer oil in industries such as petrochemical industry, synthetic fiber, synthetic resin, wood processing, nuclear fuel processing, medicine, printing and dyeing, etc., and it is particularly suitable for the application of LQD-340 organic heat carriers.

[0013] The heat transfer oil of the present invention using dicyclohexylbenzene, cyclohexylbiphenyl and hydrogenated terphenyl has better fluidity and lower kinematic viscosity, can adapt to more application scenarios, such as in winter or cold regions. It has better thermal stability and is suitable for long-term high-temperature use. Detailed embodiments

[0014] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and a single point value, and between single point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0015] The present invention provides a synthetic high-temperature heat transfer oil which, based on the total weight of the heat transfer oil, contains:

[0016] 50-88% of dicyclohexylbenzene;

[0017] 5-40% of cyclohexylbiphenyl;

[0018] 5-25% of hydrogenated terphenyl;

[0019] 0-15% of methylcyclopentylcyclohexylbenzene;

[0020] 0-10% of methylcyclopentylbiphenyl. The synthetic high-temperature heat transfer oil of the present invention is suitable for LQD-340 organic heat carriers.

[0021] The heat transfer oil of the present invention using dicyclohexylbenzene, cyclohexylbiphenyl, and hydrogenated terphenyl has better fluidity and lower kinematic viscosity, and can adapt to more application scenarios, such as in winter or cold regions. It has better thermal stability and is suitable for long-term high-temperature use.

[0022] According to a preferred embodiment of the present invention, the heat transfer oil contains:

[0023] 55 - 70% of dicyclohexylbenzene;

[0024] 10 - 30% of cyclohexylbiphenyl;

[0025] 7 - 15% of hydrogenated terphenyl;

[0026] 1 - 10% of methylcyclopentylcyclohexylbenzene;

[0027] 0 - 5% of methylcyclopentylbiphenyl.

[0028] The aforementioned heat transfer oil has better thermal stability and is suitable for long-term high-temperature use.

[0029] The heat transfer oil of the present invention can achieve the purpose of the present invention with the aforementioned composition, and there are no special requirements for its preparation method or source. For example, the heat transfer oil is obtained by physically mixing dicyclohexylbenzene, cyclohexylbiphenyl, hydrogenated terphenyl, optionally methylcyclopentylcyclohexylbenzene, and optionally methylcyclopentylbiphenyl.

[0030] For example, it is a mixture containing dicyclohexylbenzene, cyclohexylbiphenyl, hydrogenated terphenyl, optionally methylcyclopentylcyclohexylbenzene, and optionally methylcyclopentylbiphenyl obtained by separation through the same chemical synthesis method.

[0031] For example, it is obtained by mixing one or more of dicyclohexylbenzene, cyclohexylbiphenyl, hydrogenated terphenyl, optionally methylcyclopentylcyclohexylbenzene, and optionally methylcyclopentylbiphenyl separated by different chemical synthesis methods according to the target ratio.

[0032] The present invention mainly utilizes the physical properties of various substances. Therefore, isomers and synthesis methods do not affect the use effect of the components in the field of heat transfer oil, nor do they affect the kinematic viscosity at 0 °C and the deterioration rate. And, the synthesis method of the components is not limited to the experimental methods listed in the present invention. The following is a limited example, but it should not be considered that the source of the substances of the present invention is limited to the following examples.

[0033] In the present invention, there are no special requirements for the source of dicyclohexylbenzene, and various dicyclohexylbenzenes can be applicable to the present invention. They can be purchased or synthesized. For example, dicyclohexylbenzene is prepared by the hydroalkylation of benzene, and the operating conditions include, for example: a benzene / hydrogen molar ratio of 0.5 to 10.0, a temperature of 120 to 280 °C, and the catalyst is a metal-loaded acidic molecular sieve, where the metal is selected from Rh and / or Pd, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta; or dicyclohexylbenzene is prepared by the hydrogenation of biphenyl, with a biphenyl / hydrogen molar ratio of 0.5 to 10.0, a temperature of 120 to 280 °C, and the catalyst is a metal-loaded Al 2 O 3 , and the metal is, for example, selected from Rh and / or Pd.

[0034] In the present invention, there are no special requirements for the source of cyclohexylbiphenyl, and various cyclohexylbiphenyls can be applicable to the present invention. They can be purchased or synthesized. According to one embodiment of the present invention, cyclohexylbiphenyl is prepared by the alkylation of biphenyl with benzene and / or the disproportionation reaction of cyclohexylbenzene with biphenyl.

[0035] In the present invention, during the preparation of cyclohexylbiphenyl, the operating conditions for the alkylation of biphenyl with benzene include, for example: a biphenyl / benzene molar ratio of 0.05 to 10.0, a temperature of 120 to 250 °C, and the catalyst is an acidic molecular sieve, which is selected from one or more of Y, MCM-22, and Beta.

[0036] In the present invention, during the preparation of cyclohexylbiphenyl, the operating conditions for the disproportionation reaction of cyclohexylbenzene with biphenyl include, for example: a biphenyl / cyclohexylbenzene molar ratio of 0.05 to 10.0, a temperature of 120 to 250 °C, and the catalyst is an acidic molecular sieve, which is selected from one or more of Y, MCM-22, and Beta.

[0037] In the present invention, there are no special requirements for the source of hydrogenated terphenyl, and various hydrogenated terphenyls can be applicable to the present invention. They can be purchased or synthesized. For example, hydrogenated terphenyl is prepared by the hydroalkylation of benzene, the hydroalkylation of biphenyl, the hydroalkylation of cyclohexylbenzene, or the alkylation of cyclohexylbenzene with biphenyl.

[0038] In the present invention, during the preparation of hydrogenated terphenyl, the operating conditions for the hydroalkylation of benzene include, for example: a benzene / hydrogen molar ratio of 0.5 to 10.0, a temperature of 120 to 280 °C, and the catalyst is a metal-loaded acidic molecular sieve, where the metal is selected from Rh and / or Pd, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta.

[0039] In the present invention, during the preparation of hydrogenated terphenyls, biphenyl hydroalkylation is carried out with a biphenyl / hydrogen molar ratio of 0.5 to 10.0 and a temperature of 120 to 280 °C. The catalyst used is a metal-loaded acidic molecular sieve, where the metal is selected from Rh and / or Pd, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta.

[0040] In the present invention, during the preparation of hydrogenated terphenyls, the operating conditions for cyclohexylbenzene hydroalkylation include, for example, a cyclohexylbenzene / hydrogen molar ratio of 0.5 to 10.0 and a temperature of 120 to 280 °C. The catalyst used is, for example, a metal-loaded acidic molecular sieve, where the metal is selected from Rh and / or Pd, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta.

[0041] In the present invention, during the preparation of hydrogenated terphenyls, the operating conditions for the disproportionation reaction of biphenyl and cyclohexylbenzene include, for example, a biphenyl / cyclohexylbenzene molar ratio of 0.05 to 10.0 and a temperature of 120 to 250 °C. The catalyst used is an acidic molecular sieve, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta.

[0042] In the present invention, there are no special requirements for the source of methylcyclopentylcyclohexylbenzene, and various methylcyclopentylcyclohexylbenzenes can be applied to the present invention. They can be purchased or synthesized. For example, methylcyclopentylcyclohexylbenzene can be prepared by the disproportionation reaction of methylcyclopentylbenzene and cyclohexylbenzene and / or by the hydroalkylation of benzene.

[0043] According to an embodiment of the present invention, during the preparation of methylcyclopentylcyclohexylbenzene, the operating conditions for the disproportionation reaction of methylcyclopentylbenzene and cyclohexylbenzene include a methylcyclopentylbenzene / cyclohexylbenzene molar ratio of 0.05 to 10.0 and a temperature of 120 to 250 °C. The catalyst used is an acidic molecular sieve, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta.

[0044] According to an embodiment of the present invention, the operating conditions for benzene hydroalkylation include a benzene / hydrogen molar ratio of 0.5 to 10.0 and a temperature of 120 to 280 °C. The catalyst used is a metal-loaded acidic molecular sieve, where the metal is selected from Rh and / or Pd, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta

[0045] In the present invention, there are no special requirements for the source of methylcyclopentylbiphenyl, and various methylcyclopentylbiphenyls can be applicable to the present invention. They can be purchased or synthesized. For example, methylcyclopentylbiphenyl can be prepared by the disproportionation reaction of methylcyclopentylbenzene and biphenyl and / or by the transalkylation reaction of biphenyl and cyclohexylbenzene. The operating conditions for the preparation of methylcyclopentylbiphenyl by the disproportionation reaction of methylcyclopentylbenzene and biphenyl include, for example: the molar ratio of methylcyclopentylbenzene / biphenyl is 0.05 - 10.0, the temperature is 120 - 250 °C, and the catalyst is an acidic molecular sieve, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta. The operating conditions for the disproportionation reaction of biphenyl and cyclohexylbenzene include, for example: the molar ratio of biphenyl / cyclohexylbenzene is 0.05 - 10.0, the temperature is 120 - 250 °C, and the catalyst is an acidic molecular sieve, and the acidic molecular sieve is selected from one or more of Y, MCM-22, and Beta.

[0046] If the foregoing method can synthesize multiple components of the present invention, there is no need to separately separate various components. It is only necessary to separate the target multiple mixtures, and then adjust the materials as needed to obtain the heat transfer oil with the composition of the present invention.

[0047] The heat transfer oil of the present invention is particularly suitable for applications in industries such as petrochemical, synthetic fiber, synthetic resin, wood processing, nuclear fuel processing, medicine, and printing and dyeing.

[0048] The present invention will be described in detail below through examples. In the following examples, the physical property parameters were measured by the detection methods corresponding to GB-23971; dicyclohexylbenzene, cyclohexylbiphenyl, and methylcyclopentylcyclohexylbenzene were synthesized in the laboratory and obtained by rectification, with a purity greater than 99.5%, and hydrogenated terphenyl was synthesized in the laboratory and obtained by rectification, with a purity greater than 99.5%.

[0049] The present invention will be described in detail below through examples, but this does not limit the scope of the present invention.

[0050] In the examples, dicyclohexylbenzene, methylcyclopentylcyclohexylbenzene, and hydrogenated terphenyl are obtained, for example, by the hydroalkylation of benzene. The obtained product is rectified and separated to obtain methylcyclopentylcyclohexylbenzene, dicyclohexylbenzene, and hydrogenated terphenyl. Cyclohexylbiphenyl and methylcyclopentylbiphenyl are obtained, for example, by the transalkylation reaction of biphenyl and cyclohexylbenzene. The isomers and synthesis methods do not affect the use effect of the components in the field of heat transfer oil, nor do they affect the kinematic viscosity at 0 °C and the deterioration rate. The formulations of the following examples are obtained by changing the operating conditions or the preparation method or by purification, separation, and compounding. And, the synthesis methods of the components are not limited to the experimental methods listed here.

[0051] Example 1

[0052] Dicyclohexylbenzene 70%, cyclohexylbiphenyl 20%, hydrogenated terphenyl 10%, kinematic viscosity at 0 °C: 790 mm2 / s; The deterioration rate is 5.5%.

[0053] Example 2

[0054] 55% of dicyclohexylbenzene, 32% of cyclohexylbiphenyl, 13% of hydrogenated terphenyl, kinematic viscosity at 0 °C: 850 mm 2 / s; The deterioration rate is 4.5%.

[0055] Example 3

[0056] The proportion of dicyclohexylbenzene is 88%, the proportion of cyclohexylbiphenyl is 5%, the proportion of hydrogenated terphenyl is 7%, kinematic viscosity at 0 °C: 630 mm 2 / s; The deterioration rate is 6.5%.

[0057] Example 4

[0058] The proportion of dicyclohexylbenzene is 60%, the proportion of cyclohexylbiphenyl is 30%, the proportion of hydrogenated terphenyl is 9%, and 1% of methylcyclopentylcyclohexylbenzene. Kinematic viscosity at 0 °C: 600 mm 2 / s; The deterioration rate is 3.7%.

[0059] Example 5

[0060] The proportion of dicyclohexylbenzene is 60%, the proportion of cyclohexylbiphenyl is 25%, the proportion of hydrogenated terphenyl is 11%, and 4% of methylcyclopentylcyclohexylbenzene. Kinematic viscosity at 0 °C: 620 mm 2 / s; The deterioration rate is 3.5%.

[0061] Example 6

[0062] The proportion of dicyclohexylbenzene is 75%, the proportion of cyclohexylbiphenyl is 10%, the proportion of hydrogenated terphenyl is 5%, and 10% of methylcyclopentylcyclohexylbenzene. Kinematic viscosity at 0 °C: 610 mm 2 / s; The deterioration rate is 8.1%.

[0063] Example 7

[0064] The proportion of dicyclohexylbenzene is 55%, the proportion of cyclohexylbiphenyl is 20%, the proportion of hydrogenated terphenyl is 15%, 5% of methylcyclopentylcyclohexylbenzene, and 5% of methylcyclopentylbiphenyl. Kinematic viscosity at 0 °C: 550 mm 2 / s; The deterioration rate is 4.4%.

[0065] Example 8

[0066] The proportion of dicyclohexylbenzene is 85%, the proportion of cyclohexylbiphenyl is 5%, the proportion of hydrogenated terphenyl is 6%, 3% of methylcyclopentylcyclohexylbenzene, and 1% of methylcyclopentylbiphenyl. Kinematic viscosity at 0 °C: 680 mm 2 / s; The deterioration rate is 6.1%.

[0067] Example 9

[0068] The proportion of dicyclohexylbenzene is 70%, the proportion of cyclohexylbiphenyl is 14%, the proportion of hydrogenated terphenyl is 10%, the proportion of methylcyclopentylcyclohexylbenzene is 1%, and the proportion of methylcyclopentylbiphenyl is 5%. Kinematic viscosity at 0 °C: 610 mm 2 / s; deterioration rate 4.3%.

[0069] Example 10

[0070] According to Example 1, the difference is that

[0071] The proportion of dicyclohexylbenzene is 65%, the proportion of cyclohexylbiphenyl is 15%, the proportion of hydrogenated terphenyl is 20%, kinematic viscosity at 0 °C: 920 mm 2 / s; deterioration rate 8.5%.

[0072] Example 11

[0073] According to Example 4, the difference is that

[0074] The proportion of dicyclohexylbenzene is 50%, the proportion of cyclohexylbiphenyl is 25%, the proportion of hydrogenated terphenyl is 11%, the proportion of methylcyclopentylcyclohexylbenzene is 14%. Kinematic viscosity at 0 °C: 660 mm 2 / s; deterioration rate 9.8%.

[0075] Example 12

[0076] According to Example 7, the difference is that

[0077] The proportion of dicyclohexylbenzene is 70%, the proportion of cyclohexylbiphenyl is 10%, the proportion of hydrogenated terphenyl is 5%, the proportion of methylcyclopentylcyclohexylbenzene is 10%, and the proportion of methylcyclopentylbiphenyl is 5%. Kinematic viscosity at 0 °C: 650 mm 2 / s; deterioration rate 9.3%.

[0078] Comparative Example 1

[0079] The proportion of dicyclohexylbenzene is 54%, the proportion of hydrogenated terphenyl is 30%, the proportion of methylcyclopentylcyclohexylbenzene is 15%, and the proportion of methylcyclopentylbiphenyl is 1%. Kinematic viscosity at 0 °C: 2510 mm 2 / s; deterioration rate 13.5%.

[0080] Comparative Example 2

[0081] The proportion of dicyclohexylbenzene is 30%, the proportion of cyclohexylbiphenyl is 40%, the proportion of hydrogenated terphenyl is 10%, the proportion of methylcyclopentylcyclohexylbenzene is 15%, and the proportion of methylcyclopentylbiphenyl is 5%. Kinematic viscosity at 0 °C: 590 mm 2 / s; deterioration rate 31%.

[0082] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including the combination of each technical feature in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A synthetic high-temperature heat transfer oil, characterized in that based on the total weight of the heat transfer oil, the heat transfer oil contains: 50 - 88% of dicyclohexylbenzene; 5 - 40% of cyclohexylbiphenyl; 5 - 25% of hydrogenated terphenyl; 0 - 15% of methylcyclopentylcyclohexylbenzene; 0 - 10% of methylcyclopentylbiphenyl.

2. The heat transfer oil according to claim 1, wherein the heat transfer oil contains: 55 - 70% of dicyclohexylbenzene; 10 - 30% of cyclohexylbiphenyl; 7 - 15% of hydrogenated terphenyl; 1 - 10% of methylcyclopentylcyclohexylbenzene; 0 - 5% of methylcyclopentylbiphenyl.

3. The heat transfer oil according to claim 1 or 2, wherein the heat transfer oil is obtained by physically mixing dicyclohexylbenzene, cyclohexylbiphenyl, hydrogenated terphenyl, optionally methylcyclopentylcyclohexylbenzene, and optionally methylcyclopentylbiphenyl.

4. The heat transfer oil according to claim 1 or 2, wherein the heat transfer oil is a mixture containing dicyclohexylbenzene, cyclohexylbiphenyl, hydrogenated terphenyl, optionally methylcyclopentylcyclohexylbenzene, and optionally methylcyclopentylbiphenyl, which is separated by the same chemical synthesis method; or the heat transfer oil is obtained by mixing one or more of dicyclohexylbenzene, cyclohexylbiphenyl, hydrogenated terphenyl, optionally methylcyclopentylcyclohexylbenzene, and optionally methylcyclopentylbiphenyl separated by different chemical synthesis methods according to the target ratio.

5. The heat transfer oil according to any one of claims 1 - 4, wherein dicyclohexylbenzene is prepared by benzene hydroalkylation and / or by biphenyl hydrogenation.

6. The heat transfer oil according to any one of claims 1 - 5, wherein cyclohexylbiphenyl is prepared by alkylation of biphenyl with benzene and / or by disproportionation reaction of cyclohexylbenzene with biphenyl.

7. The heat transfer oil according to any one of claims 1 - 6, wherein hydrogenated terphenyl is prepared by benzene hydroalkylation and / or biphenyl hydroalkylation and / or cyclohexylbenzene hydroalkylation and / or alkylation of cyclohexylbenzene with biphenyl.

8. The heat transfer oil according to any one of claims 1 - 7, wherein methylcyclopentylcyclohexylbenzene is prepared by disproportionation reaction of methylcyclopentylbenzene with cyclohexylbenzene and / or by benzene hydroalkylation.

9. The heat transfer oil according to any one of claims 1 - 8, wherein methylcyclopentylbiphenyl is prepared by disproportionation reaction of methylcyclopentylbenzene with biphenyl and / or by transalkylation reaction of biphenyl with cyclohexylbenzene.

10. Application of the heat transfer oil according to any one of claims 1 - 9 in petrochemical industry, synthetic fiber, synthetic resin, wood processing, nuclear fuel treatment, medicine, and printing and dyeing industries.